adapted to the crowded conditions, the level of physical pathology that of animals living in an uncrowded environment. Some of the ameliorating effects of urban adaptation in human 1 suggested by the death rates from lung cancer in the United Stai controlled for the degree of cigarette smoking, these death rates are ably higher in farm-born people who have migrated to cities than ir city dwellers. In a study of Appalachian mountaineers working in factory, it was discovered that the first generation suffered from a of illness and absenteeism; their sons did not. In the rapidly growing cities of developing countries, the newcc be expected to be at the highest risk for another reason as well. A accompaniment to urbanization is the atomization or destructio family and kinship groups that provide protection and emotional s rural individuals. In the course of time, new types of groups devel cities to fulfill some of these functions, but it is often difficult, pa for newcomers, to become effectively integrated into these groups uals who are deprived of such meaningful group relationships, e> ambiguous and conflicting demands for which they have had no experiences, and frustrated at achieving their goals and aspiration: more likely to become victims of both infectious and noninfectiou Insofar as this effect exists, it is difficult to distinguish from the din quences of a rapid increase in the level of urban crowding. It should be evident from this discussion that the magnitude and the effects of crowding on human beings are highly uncertain. Mucl is needed to clarify and quantify them. CONSEQUENCES FOR CHILDREN* Many studies have been made of the effects of family size on being of children within the family. In families with many children more malnutrition and illness of children than in small families; hij tality rates among younger children; slower physical growth; and lectual development. Family size is not the only cause of these effei is probably an important element in the interacting network of cause Excessive "crowding" of children, especially in a family with mother, seems to produce the same effects as excessive numbers of That is, the effects of short spacing between births are about the those of large numbers of children in the family. *See Joe D. Wray, "Population Pressure on Families: Family Size and Child in Vol. II of this study.